Pharmacy generally began with the compounding of medicines which entailed the actual mixing and preparing of medications. Heretofore, pharmacy has been, to a great extent, a profession of dispensing, that is, the pouring, counting, and labeling of a prescription, and subsequently transferring the dispensed medication to the patient. Because of the repetitiveness of many of the pharmacist's tasks, automation of these tasks has been desirable.
Some attempts have been made to automate the pharmacy environment. Different exemplary approaches are shown in U.S. Pat. No. 5,337,919 to Spaulding et al. and U.S. Pat. Nos. 6,006,946; 6,036,812 and 6,176,392 to Williams et al. The Williams system conveys a bin with tablets to a counter and a vial to the counter. The counter dispenses tablets to the vial. Once the tablets have been dispensed, the system returns the bin to its original location and conveys the vial to an output device. Tablets may be counted and dispensed with any number of counting devices. Drawbacks to these systems typically include the relatively low speed at which prescriptions are filled and the absence in these systems of securing a closure (i.e., a lid) on the container after it is filled.
One additional automated system for dispensing pharmaceuticals is described in some detail in U.S. Pat. No. 6,971,541 to Williams et al. This system has the capacity to select an appropriate vial, label the vial, fill the vial with a desired quantity of a selected pharmaceutical tablet, apply a cap to the filled vial, and convey the labeled, filled, capped vial to an offloading station for retrieval. Although this particular system can provide automated pharmaceutical dispensing, certain of the operations may be improved. For example, in some automated pill dispensing systems such as those described in U.S. patent application Ser. No. 12/350,568 to Schedel et al., the filled pill vials may be output to an offload chute for retrieval by a pharmacist or other human operator, and an optical sensor may be used to detect the presence or absence of vials in the offload chute. However, when using an optical sensor for detection, it may be difficult to detect transparent vials, especially when the vials are empty and/or unlabeled. Also, external factors, such as ambient lighting, conditions, may affect the accuracy of the optical sensors in optically detecting the presence or absence of vials in a chute and/or other locations in the system.